1. Field of the Invention
The present invention relates to a petrol saving structure of a motor vehicle, more particularly one, which is equipped with an oxygen-detecting voltage controlling device for sending a stable voltage feedback to the engine computer such that the engine computer is prevented from making a correction through increasing amount of petrol injected through an injection nozzle, thus saving petrol.
2. Brief Description of the Prior Art
Referring to FIG. 6, a currently existing petrol saving structure of a motor vehicle includes an air filter 91, an air-regulating gate 92, a by-pass electromagnetic valve 93, and an engine 94.
The air filter 91 is used for filtering air such that the air can be mixed with petrol sufficiently, and it communicates with the atmosphere at one end, and is connected to one end of an inlet manifold 911 at the other end. The inlet manifold 911 is connected to an inlet by-pass pipe 912, and the engine 94 at the other end.
The air-regulating gate 92 is positioned in that portion of the inlet manifold 911 that faces an outlet of the air filter 91, and it is controlled by means of an engine computer for regulating airflow.
The by-pass electromagnetic valve 93 is connected to the inlet by-pass pipe 912 for regulating airflow.
The engine 94 is connected to the inlet manifold 911 at one side, and connected to exhaust pipes 941 at the other side, and it is controlled for a proper amount of petrol to be injected through an injection nozzle according to the opening angle of the air-regulating gate 92 by means of the engine computer, which petrol will be sufficiently mixed with air flowing in through the inlet manifold 911 at an optimal air/fuel ratio such that the engine rotates at a proper speed according to air inflow amount through the inlet manifold 911.
However, the above structure has the following disadvantages. When the petrol saving structure is used, and the air-regulating gate opens fifteen degrees, the engine will be set at a rotating speed of two thousand revolutions; because the inlet by-pass pipe has the by-pass electromagnetic valve connected thereto, the inlet by-pass pipe will open only thirteen degrees, and the by-pass electromagnetic valve will function to make up for the remaining two degrees; although the user will feel the accelerator pedal become sensitive, and the horse power increase, the engine computer of the engine, which is equipped with a high-tech detecting and petrol-injection controlling system, will detect leakage of the inlet manifold, and next make the injection nozzle inject increased amount of petrol to make up for the leaking fuel such that the air/fuel ratio reaches the optimal value (13.7 to 1). Consequently, petrol is wasted because the amount of petrol injected through the injection nozzle is greater than necessary.